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Vitamin D Deficiency

Insufficient levels of vitamin D, which affects bone health, immune function, mood, and many body systems.

Medical Disclaimer

This information is for educational purposes only and is not a substitute for professional medical advice. Always consult with a qualified healthcare provider for diagnosis and treatment.

Overview

Vitamin D deficiency occurs when blood levels fall below optimal ranges. Vitamin D is unique because it functions as a hormone and affects nearly every tissue in the body. It's essential for calcium absorption, bone health, immune function, muscle strength, and mood regulation.

Despite its importance, vitamin D deficiency is extremely common, affecting an estimated 1 billion people worldwide. Risk factors include limited sun exposure, darker skin, obesity, older age, living at northern latitudes, and certain medical conditions.

Vitamin D is obtained through sun exposure (skin synthesis), diet (fatty fish, fortified foods), and supplements. Many people require supplementation to achieve optimal levels, especially those who live far from the equator or have limited sun exposure.

Common Symptoms

  • •Fatigue and tiredness
  • •Bone pain and muscle weakness
  • •Frequent infections
  • •Depression and mood changes
  • •Slow wound healing
  • •Bone loss (osteopenia/osteoporosis)
  • •Hair loss
  • •Muscle cramps
  • •Poor concentration
  • •Weight gain
  • •Back pain

Key Blood Markers

Vitamin D (25-hydroxy)

Low (<50 nmol/L or 20 ng/mL is deficiency)

The primary marker for vitamin D status

Calcium

Usually normal, may be low if severe

May be low with severe vitamin D deficiency due to poor absorption

Alkaline Phosphatase

May be elevated

May be elevated in vitamin D deficiency affecting bone

Frequently Asked Questions

What vitamin D level is optimal?
While "normal" ranges often start at 50 nmol/L (20 ng/mL), many experts consider 75-125 nmol/L (30-50 ng/mL) optimal for health benefits. Levels below 50 nmol/L indicate deficiency; below 25 nmol/L is severe deficiency.
How much vitamin D should I supplement?
Doses range from 1,000-5,000 IU daily depending on current levels and individual factors. Severely deficient individuals may need higher initial doses. Testing every 2-3 months helps dial in the right dose.
Can you get enough vitamin D from sun alone?
It depends on latitude, season, skin color, and sun exposure. People at latitudes above 35°N (most of USA/Europe) can't make sufficient vitamin D from sun October-March. Many people need supplements year-round.
Should vitamin D be taken with food?
Yes, vitamin D is fat-soluble and absorbs significantly better when taken with a meal containing fat. Studies show up to 50% better absorption with a fatty meal compared to fasting.

Quick Facts

  • Key Markers:3
  • Common Symptoms:11

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